626 



THE CHEMICAL PROPERTIES OF BACTERIAL 

 GUM LEV AN. 



By Thos. Steel, F.L S., F.C.S. 



The production of gum levari by the action on sucrose of a new 

 bacillus, B. levayiiformans, isolated from samples of cane juice 

 and of sugar which had been found to be undergoing inversion, 

 is described by Mr. R. Greig-Smith, M.Sc, in the preceding 

 paper. My examination into some of the properties of the gum 

 was made on material given to me by Mr. Smith, for an abundant 

 supply of which I am indebted to him. 



The gum Avas puriHed from sugars by precipitation with alcohol 

 from solution in water. After drying at 100° C. it contained 

 0'125 per cent, of nitrogen, equivalent to 1*0 per cent, proteid. 

 The ash amounted to 1 -4 per cent. 



Deducting these constituents, which may be regarded as 

 impurities, the preparation contained 97 '6 per cent, of gum. It 

 is on this figure that the products of inversion, etc., are calculated 

 below. 



The solution of the gum in water is opalescent, less so, how- 

 ever, when concentrated than when moderately dilute. 



When a hot, strong solution is allowed to stand in the cold, it 

 forms a mucilage resembling that produced by gum arabic, and 

 does not become at all gelatinous. 



The gum is insoluble in spirit, by which it is precipitated from 

 aqueous solution. 



It is not precipitated by subacetate of lead, nor by ammoniacal 

 silver nitrate, but forms a white precipitate with ammoniacal 

 lead acetate. 



